In the related art, an intake system of an internal combustion engine with a supercharger is known (for example, refer to US2014/0318514A (Reference 1)).
The above-described Reference 1 discloses a ventilation system (intake system of an internal combustion engine with a supercharger) in an internal combustion engine with a turbocharger (supercharger). In the ventilation system in the internal combustion engine, an intake passage in which a throttle valve (negative pressure control valve), a compressor (intake side supercharger), an air cooler, a throttle valve, and an intake manifold, are disposed in this order, is connected to an internal combustion engine main body. In addition, an exhaust passage in which an exhaust manifold, an exhaust turbine, and an exhaust processing device (catalyst device) are disposed in this order, is connected to the internal combustion engine main body. In addition, in a state where a blow-by passage derived from a crankcase and an EGR gas passage derived from the exhaust passage merge into one external gas passage, the external gas passage is connected between the throttle valve and the compressor. In addition, the upstream side of the throttle valve and the crankcase communicate with each other via a fresh air introduction passage. Accordingly, while operating the internal combustion engine, a mixed gas of blow-by gas (non-combusted air-fuel mixture including combusted gas) and EGR gas (exhaust gas) is introduced to the exhaust passage by using a negative pressure which is generated at a connection part of the external gas passage as intake gas is throttled by the throttle valve, and the fresh air is supplied to the crankcase via the fresh air introduction passage.
However, in the ventilation system in the internal combustion engine described in the above-described Reference 1, since the blow-by gas passage and the EGR gas passage are connected between the throttle valve and the compressor in the intake passage in a state where the blow-by passage and the EGR gas passage merge into one external gas passage, moisture or particulate materials included in the EGR gas, and oil components included in the blow-by gas, are mixed with each other, and deposits (sediments) are more likely to be generated. In addition, as the deposits (sediments) are deposited on an inner wall of the one external gas passage, a probability that the external gas passage will block increases. Therefore, there is a problem that a sufficient ventilation performance of the internal combustion engine main body cannot be obtained.